Cutter with stripper

ABSTRACT

A cutter blade is provided with resilient means having sections for engaging the web adjacent the cut being made and these sections exert oppositely directed tensile forces on the web on the opposite sides of the cut to assist in separating the cut edges being formed. The resilient means may also cushion the blade against vibration which would cause the blade edge to chip or dent. The blade may be made of a ceramic material encapsulated in a resilient sheath with only the cutting edge of the blade exposed for cutting the web.

llited- States Patent 1191 Hunt [ Apr. 16, 1974 CUTTER WITH STRIPPER[75] Inventor: Robert F. Hunt, Concord, Tenn.

[73] Assignee: International Paper Company, New

York, NY.

22 Filed: on. 20, 1971 21 Appl.No.: 190,918

Obenshain 83/1 16 X Nassar 83/676 X 3,224,311 12/ l 965 Wagner....3,306,149 2/1967 John 3,543,402 .12/1970 Seager 130/346.53

Primary ExaminerFrank T. Yost Assistant Examiner-Horace M. CulverAttorney, Agent, or ;Firm-Fitch, Even, Tabin & Luedeka 57] ABSTRACT -Acutter blade is provided with resilient means having sections forengaging the web adjacent the cut being made and these sections exertoppositely directed tensile forces on the web on the opposite sides ofthe cut to assist in separating the cut edges being formed. Theresilient means may also cushion the blade against vibration which wouldcause the blade edge to chip or dent. The blade may be made of a ceramicmaterial encapsulated in a resilient sheath with only the cutting edgeof the blade exposed for cutting the web.

7 Claims, 5 Drawing Figures PATENVEMPR 16 I974 ROERT E Haw? CUTTER WITHSTRIPPER- This invention relates to a cutter for paper, nonwoven fabricsor other materials and to a cutting apparatus having a cutter with acutting edge which cooperates with a support across which the materialtravels.

The cutter and cutting apparatus are described herein in connection withthe slitting of long lengths of webs of paper or nonwoven fabricstravelling at high speeds and ultimately wound into large diameterrolls; but it is to be understood that the cutter and the apparatus maybe used to out various other kinds of materials not mentioned herein.Presently, nonwoven or paper webs are slit longitudinally into two ormore narrow webs as the web travels past arotating source cutter havinga hardened steel blade with a circular, thin cutting edge projectingthrough the web to engage a rotating backup mandrel across which the webtravels to a take-up winder. The thin cutting edge of the blade isusually biased to engage the mandrel. Some of the nonwoven fabricsformed of or with reinforcing filaments, for example, nylon filaments,have been found to be difficult to cut for extended periods of time.

Such nonwoven fabrics may be cut quite readily when the cutting edge issharp, but the initial sharp edge of the cutting blade dulls with use,and the quality of cut deteriorates to where the web is not separatedinto narrow webs since portions of the web at the out are not completelysevered through and fibers bridge the cut at spaced locations. Morespecifically, when severing webs of nonwoven fabrics formed of crepedtissue and nylon reinforcing filaments conventional cutters have dulledso quickly that it has often been necessary to'project an additionalblade into the cut to sever the bridging portions and complete theseparation of the slit webs.

To improve the cutting life of the blade edge before it needsresharpening or replacement, attempts have been made to use hardermaterials, but this has not materially improved cutting efficiency.Materials such as ceramics and cermets have been applied to the cuttingsurfaces but these materials are brittle and tend to chip since thecross-sectional thickness of the cutting edge is thin and the resistanceof such materials to chipping is less than metals fora thincross-sectional cutting edge. While the surfaced blades have been foundto resist wear by the web being out, these cutting edges have beenmarked by failure of the cutting edges apparently due to chipping causedby vibration or the chattering of the blade edge against the backupmandrel.

For some products, the kind and quality of cut edge is also important.For instance, paper or nonwoven fabrics which rub against or are incontact with the human skin, such as clothing, sheets or disposablediapers, preferably are formed with relative dull or nonsharp edgeswhich will not cut or irritate the skin. Thus, disposable diapers havebeen saw cut from a continuous pad with a sawblade to prevent theformation ofa clean, sharp irritating cutting edge on the product. Thus,for some paper and nonwoven products, it is most desirableto produce anon-sharp and nonirritating edge for the sheet or web product.

Accordingly, an object of the invention is to provide a new andimproved, as contrasted to the prior art, cutter and cutting apparatus.

These and other objects and advantages will become apparent from thedetailed description taken in accordance with the accompanying drawingsin which:

FIG. 1 is a fragmentary sectional view of a cutter and a cuttingapparatus embodying the novel features of the invention;

FIG. 2 illustrates the cutter of FIG. I in a diagrammatic cuttingoperation;

FIG. 3 illustrates another cutter constructed in accordance with anotherembodiment of the invention;

FIG. 4 illustrates a further embodiment of the invention shown inelevation; and

FIG. 5 is a partial sectional view taken substantially along the line 55of FIG. 4.

As shown in the drawings for purposes of illustration, the invention isembodied in a cutter 11 having a circular cutter blade 12 which isassociated with or encapsu lated in a resilient means in the form of asheath 13 of elastomeric material such as, for example, a rubber or aresilient, resinous plastic. This sheath is positioned adjacent acutting edge 15 of the blade so that when the cutting edge 15 is broughtinto slitting position to cut a web 16, as illustrated in FIG. 2, movingacross a backup means in the form of a cylindrical mandrel l7, portionsor sections of the elastomeric sheath 13 are caused to flow laterallyoutwardly from and on opposite sides of the cutting blade edge 15 andthereby tension the sheet being cut. More specifically, the sections 18adjacent the blade edge are compressed and flexed away from the bladeedge and in so flexing exert forces on the web tensioning the samebetween the sections with the result that these flexed portions assistin breaking and pulling apart the fibers and filaments in the web and inseparating them and thus separate the webs cut by the blade edge 15.

More specifically, as the blade edge 15 is brought into contact with themandrel 17, the peripheral section of the sheath on opposite sides ofthe blade edge 15 are forced apart by the wedging action of the inclinedside walls 20 of the blade 12. As the compressed sections 18 are engagedby the blade they are cammed and forced outwardly from the blade edge 15while en gaging the web 16 at areas 16a and 16b (FIG. 2) on oppositesides of the cutting edge 15. As the sections 18 are compressed andcammed outwardly by the blade side walls 20, the areas and 1612 aresubjected to forces tending to separate them as the cutting edge 15breaks or crushes the fibers joining the web areas 16a and 16b. Hence,the outwardly directed forces from the sheath sections 18 assist inseparating the fibers and in separating the web portions cut by theblade. As the fibers break or tear because of tension as well as beingsevered by the blade edge, the cut edges of the web are irregular withbroken fibers in evidence, as in contrast, to sharp cutting edges wheremost of the fibers have sharply defined cuts.

As will be explained in more detail, the sheath means may be made invarious ways to protect the cutting edge 15 by absorbing energy anddampening vibrations Y imparted to the blade. Also, the resilientsections 18 react against movement of the blade side walls 20 byfr'ictionally retarding the same and thereby retard the blade frommoving along the mandrel 17. With some forms of sheath, the resilientmaterial of the sheath is positioned between the blade and a supportingshaft therefore, to distribute and make more uniform any load applied bythe shaft to the blade body.

Referring now more specifically to the drawings, the sheath 13 is formedof two annular rings 31 of resilient materials such as, for example,rubber or a resinous plastic material such as, for example, Adidreme,made by E. l. Du Pont de Nemours. The annular rings 31 may be bonded toopposite annular sides 32 of the knife body 33. The rings 31 abut innerannular walls 35 on the blade body 33 and are similarly bonded thereto.If the knife body 33 is formed of a metal the elastomeric material maybe bonded directly thereto by known means. if the knife body 33 isfabricated from a ceramic as will be hereinafter described, a betterbond may be obtained between the ceramic knife body 33 and the sheathrings 31 by first metalizing, i.e., applying a metal coating to thewalls 32 and 35 of the knife body 33, and then bonding the elastomericrings 31 to the metal coatings.

To assist in the lateral outward displacement of the sections 18relative to the inclined blade walls 20 on the knife body 33, thesesections are free to slide relative to the inclined blade walls and arenot bonded to the inclined blade walls 20 of the blade body. Also, inthe illustrated embodiment of FIGS. 1 and 2, the cutting edge 15 isdisposed radially inwardly of outer, annular, peripheral sheath surfaces21 so that when the cutter is first positioned with the surfaces 21abutting the web, the blade edge 15 will be disposed radially inward ofthe web and spaced therefrom by a gap such as, for example, threethirty-seconds of an inch. As the loading pressure for the cutter iscontinued, the cutting edge 15 continues toward the mandrel 17 andthrough the gap to abut the web 16 and then through the web 16 to engagethe mandrel 17. As the cutter blade rtates, the sections 18 first engagethe web and spread as the cutting edge moves into slitting engagementwith the web traveling therepast.

When portions of the blade 11 rotate out of contact with the web 16, thecompressed sections 18 on the sheath return to the position illustratedin FIG. 1. The gap between the sections 18 at the cutting edge 15 isdefined by inwardly extending radial, parallel walls 49. The dimensionsof the gap used may be quite small, for example, about one thirty-secondof an inch in width between the parallel walls 49 and up to threethirtyseconds of an inch or more in depth depending upon the materialbeing cut.

When the cutter body 33 is formed of a ceramic material, it is preferredthat the cutting edge 15 have a slightly curved cross section, forexample, formed with curved or arcuate radius of five to ten thousandthsof an inch. Thus, the cutting edge 15 need not be a sharply honed fineedge as with conventional score cutting metal blades as the fibers aretensioned to separate when crushed and broken by the cutting edge 15.Also, rather than having a very finely tapered section between the walls20, as in a metal section blade, the walls 20 may define a blunter crosssection as illustrated. This construction results in additional strengthagainst chipping. The wider angle B between the inclined blade walls 20for a ceramic blade should be between about 45 and 90. With the ceramicblade the resilient compressed sections 18 frictionally retard movementsof the cutting faces 20 out of their predetermined path and also act toabsorb energy when being compressed by the blade. As the ceramic ishard, a Rockwell 45N hardness of 80 or more, it wears considerably lessthan does a softer metal steel blade.

The ceramic from which the blade is made is preferably a fine grained,smooth, fired element. Preferably, the crystal size of the particles inthe ceramic are 10 microns or less and the fired element has a Rockwell45N hardness of over about 80. Preferably, the ceramic has a surfacefinish in microinches (average) of 40 or less. The void volume afterfiring is preferably less than 12 percent and most desirably sevenpercent or less. Suitable ceramic materials from high purity aluminumoxide are manufactured by the Coors Porcelain Company of Golden, Colo.under the designations AD9O and AD999.

The mandrel 17 may be formed of a hardened steel or ceramic material.The illustrated mandrel 17 may be made of ceramic and in the form of ahollow cylinder.

having an outer cylindrical face to abut the blade edge 15. Theillustrated multi-ply web may be, in this instance, formed of inner andouter plies of creped tissue 53, 54 with inner reinforcing filaments ina layer 55. The reinforcing filaments may be of quite small size, forexample, they may be made of nylon threads or a tow of nylon which hasbeen spread into wide web and then secured to and between the respectiveplies of creped tissue.

In'the embodiment illustrated in FIGS. 1 and 2, the body of the cutteris formed with a central hub or flange having an inner circular wall 57which may be attached to a rotatable supporting shaft 58. As thesupporting shaft turns, wear will be distributed over the entirecircumferential cutting edge 15. With the cutter illustrated in FIGS. 1and 2, the ceramic body 33 is connected directly to the rotatablesupport shaft. Hence, the spring forces urging the cutting edge 15 toengage the mandrel are applied directly to the cutter body.

In the embodiment of the invention illustrated in FIG. 3, the sheathitself is formed with a circular hub portion 61 to fit on the supportingshaft, and the ceramic blade body 63 is, except for its cutting edge15a, almost completely encapsulated in the elastomeric material. Thus,the force from the supporting shaft for urging the blade edge 15aagainst the mandrel 17 is applied through the compressible elastomericmedium, and the compressible medium is able to compress and expand toaccommodate variations in loads applied by the shaft with a more uniformapplication of force at the blade edge. Stated differently, thisadditional cushioning of the blade body 63 from the supporting shaftresults in a more even application of a load to the blade edge when thesupporting shaft 58 is applying uneven loads or during vibration of theshaft and is desirable when a ceramic blade is employed.

As illustrated in FIG. 3, the sheath may be in the form of an annularbody within which is a ring shaped blade body 63 having a circular,outer cutting edge 15a. The encapsulated blade body 63 is bonded alongan inner circular wall 65 and a pair of radially extending side walls 67to the surrounding sheath. The inclined blade side walls 20a arepreferably not bonded to the adjacent sections 18a of the sheath. Thegap between the sections exposes the blade edge 15a, and the sections18a function as the similar sections 18 described in connection with thepreviously described embodiment of the invention. That is, thesesections 18a of the sheath adjacent the inclined blade walls 20a arefree to be displaced in the manner previously described for the sections18a as the blade edge 15a is brought into engagement with the web and iscaused to penetrate therethrough as it rotates and maintains engagementwith themandrel. In the embodiment of FIG. 3, the

blade body 63 may be made of either metal or ceramic. When the body isformed of ceramic, it is preferred to metalize the radial side walls 63so that the elastomeric may be tightly bonded thereto over wideareasthereof, rather than only at spaced points of contact.

Turning now to the further'embodiments of the invention illustrated inFIGS. 4 and 5, common numerals with a suffix b have been applied to thisembodiment to elements which are identical to those previouslydescribed. In the embodiment of the invention of FIGS. 4 and 5, the ringshaped blade body 63b is smaller than the slitter body 63 (FIG. 3). Withthe forcing of the blade edge b against the mandrel and surfaces 21bagainst the web, the sections 18b will be compressed and displacedradially from the blade edge 15b as in previously described embodiments.As the sections 18b displace inwardly, they also flow laterally totension the web.

In this instance, the sheath 13b has a particularly large portion or hub61b intermediate the supporting shaft (not shown) which engages a sheathhub wall 69b and the blade body 63b. Thus, vibrations and uneven loadsbeing applied will be cushioned in the elastomeric hub 61b and cuttingedge 15b of the ceramic body is being protected against undue pressureor chattering which would cause the same to crack or chip.

By way of example only, dimensions for one specific embodiment of theinvention will be given, namely for the embodiment illustrated in FIG.5. The sheath has a 3.062 inch outer diameter with the blade edge 15bterminating three thirty-seconds inch radially inwardly of the outercircumference of the sheath. A inch diameter circular opening isprovided at the hub. The width of the sheath is three-eighths inchbetween the outer flat side walls 73 of the sheath. In this instance,the angle B between the inclined blade walls 20b is 90. The internalcutter body 63b is formed of ceramic, while the outer resilient sheathmaterial is formed of an elastomeric such as Adidreme. The sheath 13 isbonded to the ceramic by an adhesive such as an epoxy adhesive.

From the foregoing, it will be seen that the present invention providesa cutting blade which may be encapsulated in a resilient sheath toprotect the blade edge from chipping or otherwise being damaged shouldthe blade be vibrated relative to a supporting backup roller or mandrel.Also, it will be seen that the unique compressed portions operate toabsorb energy and protect the blade, particularly if the same has aceramic cutting edge. Thus, there may be provided a cutting device whichincludes an elastomeric body with a ceramic insert having compressedportions adjacent a cutting edge on the ceramic insert to protect thelatter from chipping due to vibrations.

Moreover, the invention also discloses placing the web in tensionbetween oppositely directed forces which act in directions transverse tothe direction of the cut being formed so that the fibers are pulledapart and are torn rather than being sharply cut as would be irritatingto the skin if the cut product is used in clothing or diapers. Thecutter is also made so that the same may be made simply and cheaply.

While a preferred embodiment has been shown and described, it will beunderstood that there is no intent to limit the invention by suchdisclosure, but rather, it is intended to cover all modifications andalternate constructions falling within the spirit and scope of theinvention as defined in the appended claims.

What is claimed is:

l. A cutter for cutting a piece of material comprising a blade bodyformed of a hard brittle non-metallic material, a circular cutting edgeon said blade body for cutting the material, resilient means fastened tosaid blade body, and compressible sections on said resilient means forengaging said material and for being com pressed when said cutting edgeis cutting the material for absorbing energy and dampening vibrations toprevent chipping of said circular cutting edge, said resilient meanssubstantially encapsulating said blade body and being bonded theretoalong radially extending walls of said body, said blade body beingformed with inclined walls adjacent said cutting edge for camming saidsections of the resilient means outwardly from said cutting edge.

2. A cutter in accordance with claim 1 in which said resilient means isformed of an elastomeric material and in which means bonds saidelastomeric material to said blade body over a major portion thereof andin which said compressible sections are unbonded to said blade body andfree to move relative to said cutting edge.

3. A cutter for slitting a web comprising an annular blade body formedof ceramic material, an outer continuous, uninterrupted circular cuttingedge on said ceramic blade body for engaging and cutting the web,inclined side walls on said blade body adjacent said circular cuttingedge, and elastomeric means fastened to said blade body for absorbingenergy and dampening vibrations to prevent chipping of said circularcutting edge, said elastomeric means having portions thereof engagingsaid inclined walls of said blade body, said portions extending radiallyoutward of said cutting edge and free to slide relative to said inclinedside walls, said portions being compressible radially inwardly to slidealong said side walls to expose said cutting edge for engagement withsaid web, and said portions being displaceable laterally relative toportions of said blade body in a direction transverse to that of the cutto tension the web during cutting.

4. A cutter in accordance with claim 3 in which outer, circular, webengaging surfaces on said elastomeric means project radially outwardlyof said cutting edge until said cutting edge is forced into and throughsaid web, said web engaging surfaces being displaced radially inwardlyfrom the cutting edge by a distance equal to the thickness of the web.

5. A cutter in accordance with claim 4 in which the portions of saidelastomeric means engaging said inclined surfaces are separated by a gapthrough which said cutting edge may move to engage said web.

6. A cutter in accordance with claim 3 in which said elastomeric meanscovers substantially all of said blade body except for the cutting edge.

7. A cutter in accordance with claim 3 in which said inclined walls onsaid blade body diverge outwardly from said cutting edge and include anangle of from 45 to

1. A cutter for cutting a piece of material comprising a blade bodyformed of a hard brittle non-metallic material, a circular cutting edgeon said blade body for cutting the material, resilient means fastened tosaid blade body, and compressible sections on said resilient means forengaging said material and for being compressed when said cutting edgeis cutting the material for absorbing energy and dampening vibrations toprevent chipping of said circular cutting edge, said resilient meanssubstantially encapsulating said blade body and being bonded theretoalong radially extending walls of said body, said blade body beingformed with inclined walls adjacent said cutting edge for camming saidsections of the resilient means outwardly from said cutting edge.
 2. Acutter in accordance with claim 1 in which said resilient means isformed of an elastomeric material and in which means bonds saidelastomeric material to said blade body over a major portion thereof andin which said compressible sections are unbonded to said blade body andfree to move relative to said cutting edge.
 3. A cutter for slitting aweb comprising an annular blade body formed of ceramic material, anouter continuous, uninterrupted circular cutting edge on said ceramicblade body for engaging and cutting the web, inclined side walls on saidblade body adjacent said circular cutting edge, and elastomeric meansfastened to said blade body for absorbing energy and dampeningvibrations to prevent chipping of said circular cutting edge, saidelastomeric means having portions thereof engaging said inclined wallsof said blade body, said portions extending radially outward of saidcutting edge and free to slide relative to said inclined side walls,said portions being compressible radially inwardly to slide along saidside walls to expose said cutting edge for engagement with said web, andsaid portions being displaceable laterally relative to portions of saidblade body in a direction transverse to that of the cut to tension theweb during cutting.
 4. A cutter in accordance with claim 3 in whichouter, circular, web engaging surfaces on said elastomeric means projectradially outwardly of said cutting edge until said cutting edge isforced into and through said web, said web engaging surfaces beingdisplaced radially inwardly from the cutting edge by a distance equal tothe thickness of the web.
 5. A cutter in accordance with claim 4 inwhich the portions of said elastomeric means engaging said inclinedsurfaces are separated by a gap through which said cutting edge may moveto engage said web.
 6. A cutter in accordance with claim 3 in which saidelastomeric means covers substantially all of said blade body except forthe cutting edge.
 7. A cutter in accordance with claim 3 in which saidinclined walls on said blade body diverge outwardly from said cuttingedge and include an angle of from 45* to 90*.